I started playing this game as I really liked the game play of Fallout 3, but I prefer games with swords and a more medieval feel. Ahhh Oblivion, it has everything I was looking for. I also have not even started into the main quest since I had installed the expansions right away. Following each side quest as it came, I was lead to the expansion very early, not that I mind at all! The game is quite challenging, but keeps you entertained and wanting more. I have put 16 hours into it so far over the past few weeks. This is basically the only game I play other then the odd DS game. The beginning is slow, but once you get past that, it's awesome. You can be pretty much any kind of character you want. Make sure you start increasing your skill levels quickly. I just drifted through the first part and had a hard time with a few quests as my needed skill levels were far too low. But now after some work, it's becoming a bit easier to get through each quest. I'm currently in the Shivering Isles and just finally started working on the main quest of that expansion. Honestly you can get lost in what seems to be never ending side quests (not that that's a bad thing!!!)
The game of the year edition is the best one you can get. It's the same price as the standard Oblivion game, but comes with the expansions. Save yourself the money down the road, just buy this one. You won't regret buying it, unless you really don't like a game that goes on forever!!!!!